code: def test_windbarbs_color_op(self):
      barbs = WindBarbs(
          [
              (0, 0, 0, 1, "#000000"),
              (0, 1, 0, 1, "#FF0000"),
              (0, 2, 0, 1, "#00FF00"),
          ],
          vdims=["A", "M", "color"],
      ).opts(color="color")
      plot = mpl_renderer.get_plot(barbs)
      artist = plot.handles["artist"]
      self.assertEqual(
          artist.get_facecolors(),
          np.array([[0, 0, 0, 1], [1, 0, 0, 1], [0, 1, 0, 1]]),
      )
  
file_path: geoviews/geoviews/tests/plotting/mpl/test_chart.py
imports: import numpy
  import xarray
  import geoviews
  from geoviews.element import WindBarbs
  from holoviews.tests.plotting.utils import ParamLogStream
  from geoviews import Store
  from test_plot import TestMPLPlot
label_desc: Use image node_id 5 for calling the TestWindBarbsPlot obj's underlying member method code with example usage: obj.test_windbarbs_color_op() without return types